Starter circuits are well known for energizing electric motors by connecting the motor's windings to an external source of power. Starter circuits typically employ a plurality of contacts which are selectively opened and closed to connect the motor terminals to the power source. Proper operation of the electric motor is dependent on proper operation of the contacts in the starter circuit. In known systems, the starter circuit must be disassembled and physically examined to detect and diagnose the cause of the circuit's failure. This process is undesirable because it is costly and time consuming.
One known application for electric motors is to drive chiller compressors in large heating, ventilation, and air condition (HVAC) systems. The starter circuit cycles the motor on and off to operate the compressor and control the temperature of water in the chiller circuit. In such applications, motor failure can damage the compressor and shut down the HVAC system, resulting in expensive repair costs and reduced office productivity. The problem is magnified when the motor is part of an HVAC for a large office building, where failure of the HVAC system can result in reduced or lost productivity on the part of a large number of individuals.
The present invention is directed to overcoming the above-mentioned problems by providing a system which automatically detects and diagnosis electrical faults in motor starter circuits.